In bicarbonate dialysis for the removal of toxic substances from the blood, the problem arises that bicarbonate and calcium form a poorly soluble precipitate. The components in bicarbonate dialysis are therefore kept separate as sodium bicarbonate in the basic component and as calcium chloride, in the acid component, and then mixed only in the machine itself or shortly before use.
In spite of this measure, seed crystals form in the dialysis machine, which in time leads to extensive deposits of calcium carbonate. For this reason, it becomes necessary to decalcify a dialysis machine from time to time. The usual decalcifying agents are, for example, acetic acid or citric acid.
U.S. Pat. No. 5,326,476 teaches how to introduce a manually operable or time-controlled decalcification cycle.
These decalcification methods prove to be disadvantageous to the extent that the manual selection of a decalcifying program must be made by service personnel, which as a rule turns out to be very time-consuming. Time-controlled decalcification, moreover, has the disadvantage that decalcification is effected even when the degree of calcification would not yet require such decalcification. This leads to unnecessary demands being placed on the decalcification device. Furthermore, the dialysis machine is not available for actual treatments during this period.